1. Field of the Invention
This present invention relates to agricultural vehicles.
2. Description of the Prior Art
There is on-going concern for future agricultural productivity, given the expanding world population. This concern is further exacerbated by the practice of using feed grain crops for making motor vehicle fuel. It is paramount that we make the best possible use of agricultural resources. One way to do this is to greatly expand irrigation by distributing water on a continental basis. This enlargement of agricultural operations could lead to a need for far more agricultural workers. Hopefully, we can find a way to do this within a legal immigration framework. Real progress could be based on a new kind of apparatus that would enhance productivity of workers and make the work into a more attractive activity. The right kind of new vehicles could also make possible a higher use of land, where the commonly allotted space for tractor passage through plantings could be reduced, thus even further improve usage of agricultural resources.
Some kinds of agricultural work are hard, slow, and uncomfortable. It is difficult to find workers and pay them enough to get them to do such tasks. To improve this situation with a machine requires both better productivity and greater comfort of the worker. Productivity has to be better per worker in order to make the cost of the machine affordable. Worker comfort has to be provided to attract worker, but also to enable more effective and sustained performance of tasks. Cost of the machine has to be compatible with expectations for improved productivity. Perhaps of greatest importance is the need for energy efficient operation. The intent is that the wages payable would ultimately increase. Worker safety must be carefully considered in developing new apparatus.
Compared with most generally familiar vehicles, agricultural vehicles of the sort that would significantly assist farm workers have significantly different performance requirements, and some of these offer potential for unique new system solutions. The biggest of these is the fact that for manual work, unusually low speed is desirable. Another key difference is that the low seat that would enable workers to reach to the ground would mean that conventional notions of how to stabilize a vehicle are inapplicable; particularly, a wide wheel base is not needed. Furthermore, the low operator riding position means that stability need not be so absolute since a roll over event would not be particularly hazardous; as we would normally think of such events for farm tractors. A design freedom is the fact that the overall length of a vehicle oriented toward row crop work can be quite large, enabling a vehicle and various ancillary equipment configured in a narrow but long train.
We look at the historical background for apparatus of this sort in the vast field of agricultural vehicles. Not much is found in the way of mechanization to realistically aid hand work in the fields. Rather, the tendency seems to be to develop tractor based solutions or tractor like systems. Tractors make it possible for some kinds of crops to automate the work and to provide very comfortable cab conditions. For some types of crops this leads to very successful operations utilizing ever larger tractors and harvesters of many types. However, the present need seems to call for different approaches. In many situations, the needed work can simply can not be done from a large vehicle because of the need for hand work close to the ground or for workers to be in positions relative to growing crops that would be awkward from large vehicles. Large vehicles are often not desirable because the crops themselves interfere with access by such vehicles, and unfortunately, this can lead to fanning methods where crop spacing does not make the best possible use of land resources, simply because land must be reserved to allow for the vehicle to pass.
An example situation where the vehicle prevents crop spacing that would make the best use of land resources is shown in U.S. Pat. No. 3,546,856 Hiyama 1970, FIG. 2. Somewhat better, but still intrusive is the apparatus of U.S. Pat. No. 4,250,700 Horn et al. 1981. A farming system where it is desirable to enable both the worker and vehicle to pass under growing crop vines as illustrated by the U.S. Pat. No. 3,546,856 Hiyama 1970, FIG. 1 and U.S. Pat. No. 5,423,166 Scott 1995, thus showing the disadvantages of vehicles of the size range usually found in farm vehicles. Further, U.S. Pat. No. 5,423,166 Scott 1995 illustrates the intrusiveness of both grape acquisition machinery and the associated trailer by which harvested grapes are collected.
There are prior art vehicle configurations that have been invented with these purposes in mind. U.S. Pat. No. 3,589,744 Hansen 1971 illustrates an apparatus intended to function as an aid to workers. This seems well suited for row crop work. Though the invention U.S. Pat. No. 3,589,744 Hansen 1971 seems to be useful, it is complicated. Conventional wheels with balloon type tires mounted are arranged in a three point stabilizing form, generally like many farm tractors, but also harking back to the three wheeled Morgan roadster of long ago. This is adapted to working on low growing crops with over-arching structure that allows passing over crop rows, but all this leads to complicated equipment, when simplicity is needed to allow inexpensive construction. Still this invention by Hansen is successful in providing a low seat for a worker that enables low crop access, all the way to ground level. Hansen shows one wheel that is relatively large which would help hold down drag when traversing over soft earth, but this of course does not indicate an attempt to use this for stability.
A hard cylindrical wheel concept was disclosed in prior application U.S. Ser. No. 13/199,968 Bullis 2011 in connection with an off road vehicle system intended substantially for agricultural purposes. That invention included a wheel made of thin steel in the form of a hollow cylinder including end caps. Slats were laid on the outer cylinder surface for providing a tread and for strengthening the ground contact surface, and it was noted that these could be rubber coated.
That invention U.S. Ser. No. 13/199,968 Bullis 2011 has the purpose of enabling operation in a narrow row space between row crops where a low seated worker would have ready access to plantings by virtue of a low seat, that seat being adjustable in height as appropriate for the work.
U.S. Pat. No. 2,583,358 Cesan 1952 shows a garden tractor that also relates to these general objectives, though it utilizes conventional pneumatic tired wheels in a conventional four wheel arrangement. Some stability would be achieved due to the weight of the low seated worker, when that is the position of the seat, but the conventional tires would not provide the stability of the hard wheel of Ser. No. 13/199,968 Bullis 2011. Further, the stability that would be achieved under guidance of U.S. Pat. No. 2,583,358 Cesan is particularly called into question by the highly placed machinery, especially the engine shown. It appears that stability issues mean that the design of U.S. Pat. No. 2,583,358 is incapable of operating in the very narrow row space that is possible with U.S. Ser. No. 13/199,968 Bullis 2011. The explicitly stated function of straddling the row of plantings would derive from this limitation, instead of the otherwise operation entirely between rows of plantings.
The individual wheels of that U.S. Pat. No. 2,583,968 Cesan 1952 invention are narrow in width and relatively small in diameter, which means that they would have relatively small ground surface contact and would sink into dirt such that significant loss of energy would occur when moving. U.S. Ser. No. 13/199,968 Bullis 2011 particularly addresses this effect using the wide, large diameter, hard wheel system to spread load over the ground surface.
Continuous track vehicles serve to enable operation on soft dirt. A wide variation of such a track would offer lateral stability to prevent roll over, should it be used for that purpose, and the included wheels with the track could provide a wide wheel base if needed. The wide range of use of tracked vehicles in agriculture is represented by U.S. Pat. No. 1,376,649 Schneider 1921 and U.S. Pat. No. 4,683,969 Littau 1987. U.S. Pat. No. 7,543,664 Nelson 2009 shows a rubber version, and though this is not indicated, this could be adapted to provide stability as well as load spreading benefits. Generally, vehicles using tracked wheel systems arrange for the tracks to act in widely spaced pairs to provide stability. Rubber forms of tracked systems are used in snow-mobiles, where the single track contributes somewhat to vehicle stabilization.
Comparing again to U.S. Pat. No. 3,589,744 Hansen 1971, a simpler vehicle would be the recumbent bicycle as illustrated with a sidecar in U.S. Pat. No. 6,565,106 Lopez 2003. With or without a motor or engine this at least shows the basic simplicity needed. A tricycle form of this recumbent bicycle is an obvious variation that can be occasionally seen in use, but this would be still quite useless for the present purpose given that these wheels, though large in diameter, are narrow such that they would sink in soft dirt and cause much resistance to vehicle movement. The obvious tricycle form often includes wide, laterally spaced wheel sets; significantly wider than what would be desired for carrying a worker between narrowly spaced rows.
A very simple aid to workers would be the wheeled stool of U.S. Pat. No. 3,614,120 Cicero 1971 where a seat is provided with a seat back at a slanted position that would make low work more comfortable. This invention shows wide wheels but these are shown as they are mostly for convenience, as they are indicated to be typical rubber balloon tires. Stability for this “Chair Cycle” depends on the use of the legs and feet of the worker, not a lot differently from the way one legged milk stools were stabilized by the user. Though perhaps this is a useful apparatus, it can not be considered in the category of significant mechanization.
The impediment to progress of the widely used rubber, balloon, tractor tire such is indicated in U.S. Pat. No. 3,589,744 Hansen 1971. This works fine where there is a pair of widely spaced wheels that achieves stability, but by itself offers little resistance to rolling sidewise. But wide spacing is exactly what we are not looking for, in order to accomplish the present purposes for enabling more effective crop work.
Curiously, tractor tires of the 1920s utilized hard steel wheels with large spikes bolted to them, where these spikes were called lugs. Because the typical farmer used regular roadways to get tractors from field to field, these lugs caused much disruption of smooth road surfaces. All this went away with inflated rubber tires of the mentioned balloon type. Lugs might not matter to stability, and they could be advantageous in a low speed vehicle.
Searching for solid wheels that would improve stability with a narrow wheelbase turned up U.S. Pat. No. 1,210,056 Fairman 1916 where a narrow vehicle is fitted with hard wheels. This vehicle is questionable as to safety given the high seat position, and of course this configuration does not suggest any interest in enabling hand work on low crops. A tractor utilizing hard wheels configured of lateral slats overlaid with slanted gripping ridges is shown in U.S. Pat. No. 2,560,384 Crain 1951. Though far from the field of farm vehicles, a relevant solid drum wheel is shown in the baby carriage for use in soft dirt of U.S. Pat. No. 5,158,319 Norcia et al. 1992, though there is no low seat for farm work and no special stabilizing purpose involved other than that of conventional baby carriage wheels.
U.S. Pat. No. 6,752,228 Aoyama 2004 reminds us of a function of agricultural vehicles depending on existence of tow bar capabilities, but it also illustrates the difficulty that is encountered in making the seat position truly low. This particular invention is announced as one that enables a low profile operation.
The previously mentioned invention U.S. Pat. No. 2,583,358 Cesan 1952 is pertinent in that it is a form that enables work by a low seated worker. It is configured to enable the vehicle to straddle a row of plantings such that a worker could reach down between low, side rails and tend such plantings. Though U.S. Pat. No. 2,583,358 Cesan enables access directly in front and below the worker, the side rails that would interfere with work to the side at low heights.
FIG. 1 (prior art) shows the side structure of the previously invented vehicle U.S. Ser. No. 13/199/968 Bullis 2011. This vehicles is well suited for use in row crop work on a field 102 tending planted rows 103. The narrow vehicle 101 is configured to be narrow in width 110 to fit in a single row space 105 between two rows of plantings 104, driving in forward direction indicated 109. This particularly long 122 vehicle is designed in recognition of the generally long available space of a large field, thus the equipment is distributed over length rather than width as with typical vehicles. Though light weight is possible with a box-like general structure, the side panels and upper rails limit access to field crops. Access to plants at the ground level is troublesome due to both the floor and side structure of this vehicle.